Translation:I hurt your arm and I want to put on a bandage.
The good thing about such sentences where the word to learn is out of context, is that I'll remember the meaning of it forever (probably both meanings). I will remember that curativo means dressing as well as bandage. Whereas a sample sentence where it can easily be understood from the context that curativo is obviously dresssing doesn't help much, because if I hear the word curativo in a similar, but a bit complexer context next time (which is what the real life offers most of the time) I will recognize the context (thinking: hey I heard curativo in this context before) and won't be able to recall the meaning of curativo. I am supportive of Duolingo's approach, as long as it is not too often repeated, causing alienation.
Becky (I am English), if I said I wanted to make a bandage for it, I would literally mean that I wanted to make a bandage - either a temporary one out of maybe a silk scarf, or somehow get the materials that make up a bandage and construct them together to make an actual bandage. I think my closest sentence to what Duolingo mean here would be "(sorry) I hurt your arm, (please) let me/may I, put a bandage on it"